Breakdown of the k-conservation rule in Si nanocrystals

2019-10-22 03:57:28

Si nanocrystals phonon confinement transitions

责任者: Kovalev, D.;Heckler, H.;Ben-Chorin, M.;Polisski, G.;Schwartzkopff, M.;Koch, F. 单位: Dept. of Phys., Tech. Univ. Munchen, Garching, Germany 来源出处: Physical Review Letters(Phys. Rev. Lett. (USA)),28 Sept. 1998,81(13):2803-6 摘要: We show that light emission from different systems of silicon nanocrystals does behave as expected for indirect-band-gap quantum dots. Photoluminescence excited on the low energy part of the distribution of Si nanocrystals exhibits a set of narrow peaks associated with Si TA and TO momentum-conserving phonon-assisted optical transitions. These spectra allow us to determine the ratio of no-phonon transitions to TA and TO phonon-assisted processes over a wide range of confinement energies. The ratio between these recombination channels changes by 2 orders of magnitude with increasing confinement energy, for confinement energies above 0.7 eV the radiative transitions are governed by no-phonon quasidirect processes 关键词: elemental semiconductors;nanostructured materials;photoluminescence;silicon;k-conservation rule breakdown;Si nanocrystals;light emission;indirect-band-gap quantum dots;photoluminescence;momentum-conserving phonon-assisted optical transitions;no-phonon quasidirect processes;Si